This invention relates to a rubber plug for a waterproof connector and more particularly to a rubber plug wherein the plug forms a seal between a housing and a wire within the waterproof connector.
One known rubber plug for a waterproof connector is shown in FIGS. 4 and 5. A rubber plug 2 of a cylindrical shape having a through hole 2a extending along a centerline thereof for passing a wire 1 therethrough has two flange-like collars 2b formed at a rear end portion 7 thereof. A front end portion 5 of the rubber plug has an outer diameter such that the front end portion 5 can be compressively clamped by an insulation barrel 3a of a terminal 3 with the wire 1 passing through the front end portion 5.
On the other hand, a connector housing 4 (FIG. 5) has a tubular terminal-receiving chamber 4a for retaining and holding the terminal at its front portion 8, the terminal receiving chamber having an open rear end portion 9. The open rear end portion 9 has a diameter such that the collars 2b are held in tight contact with the peripheral wall when the rubber plug 2 and the wire 1 are inserted into the housing 4.
The wire 1 is passed through the through hole 2a of the rubber plug 2, and a covering or insulating material is peeled from the front end portion 5 of the wire. The front end portion 5 of the rubber plug 2 is fixedly secured to the insulation barrel 3a of the terminal 3 by compressive clamping, and a conductor or exposed portion of the wire 1 is connected to a wire barrel 6 of the terminal 3 by compressive clamping. When the terminal 3 is inserted into the terminal receiving chamber 4a of the connector housing 4, the terminal 3 defining the leading side is retained at the inner end portion of the terminal receiving chamber 4a, and the rubber plug 2 at the rear end 9 of the terminal is received in the terminal receiving chamber 4a in intimate contact with the peripheral wall of the chamber, with the collars 2b being slightly elastically deformed.
When water is poured on the open end 9 of the terminal receiving chamber 4a, the intrusion of the water is prevented because of the intimate contact between the peripheral wall of the terminal receiving chamber 4a and the collars 2b of the rubber plug 2, thereby achieving a waterproof effect.
In the above conventional rubber plug for a waterproof connector, however, if the rear end face 7 of the rubber plug 2 is not flush with the open end of the terminal receiving chamber 4a, a water collecting recess R may be formed. In such a case, when the wire vibrates, although water will not intrude immediately, a gap is formed between the collars 2b and the peripheral wall of the terminal receiving chamber 4a. This vibration allows the collected water to intrude into the terminal receiving chamber 4a.